February/March 2021 - Frigid or Flop? Pattern/Longterm Forecast Thread.

[Daniel Boone]

If there's flow problems, it does make you wonder if others are affected. If so, makes sense the sudden fluctuations. 

[tnweathernut]

16 minutes ago, PowellVolz said:

Does this effect other mods?


.

I'm not sure which models use that data.  Wish I had a better understanding.

[Wurbus]

Nice hit for the deep south on Valentine's weekend. Atlanta would be wrecked on that run.

[Carvers Gap]

Will be interesting to see how this plays out. Both the CMC and GFS have extreme AN high pressure just after d8 dropping into the Canadian prairie and Montana.  That is syncs nicely with the MJO looks from the morning.   

[Greyhound]

2 hours ago, Shocker0 said:

Wow, in less than two days our projected temps on Monday went from 22/5 to 46/28 here.

Your username sums up my reply

[Carvers Gap]

1 hour ago, Holston_River_Rambler said:

Yeah, F5wx says it is a new 10km resolution version. I'm just not sure why or if other sites have or will start using the new one. Hopefully it is better than the Ukie we have had so far this winter. I was actually thinking about cancelling F5 subscription since I only use it for the UKMET precip. maps and it hasn't had a hot hand very often if at all this winter.

What is the knock on the UK...feel like I have missed something?  UK is always really amped.  Bout the only thing I have used it for (other than cold yesterday) is to see if it gives me a clue to the Euro run.  

[Carvers Gap]

I don't think extreme cold is off the table.  Of course nothing to do with weather and climate forecasting is a certainty.   Now that modeling is working out the details with the weekend nada storm, seems to be getting a better handle on when the cold will arrive.  I will say this (and it is no certainty), but if we go MJO phase 8, have a -NAO, and have incredibly cold air in NA...that cold is likely coming into the SE.  If we like the idea that the Euro caved to US modeling this weekend, it is worth noting that the US MJO was very aggressive in racing across phase 7.  I am not sure if it is right, but it is worth noting.  Honestly, kind of exciting seeing that type of cold on a map.  

[Matthew70]

Hopefully that cold does not suppress the storm track.  Also call me skeptical.  Another 8-10 days out.  It’s a mirage that seems to never get closer. 

[Wurbus]

Not sure if it means all that much at this point, but there are still 4 GEFS members that still have the weekend storm showing snow in our area.

[fountainguy97]

Interesting that there are still 4-5 GEFS members with a significant snow for the 84-100 hr storm.  Seems like that system still has some wiggle room.  A lot of energy up at H5 that could change. Although no OP support to be found. Likely a no show.

[Carvers Gap]

Everyone, take a look at phase 7....Now, take a look at what next week is trending towards.  The MJO is driving the bus in short term modeling.

Since the US modeling is winning some battles right now(no surprise...Euro is again mortal during shoulder season).  The EMON looks nearly identical, but actually goes into 8.  This is why I think medium and LR modeling may well be right on the potential for severe cold.

As for skepticism, people who are scientists should take it in healthy doses every day.  I am a natural skeptic.  The best problem solving teams always need people who say, "Wait a minute, have you thought about this?"  Group think is bad mojo in my book.  

[Carvers Gap]

Now take a look at next Weds on the 12z GEFS.  I cherry picked this frame(there aren't many warm ones after Sunday).  It is Tuesday, and that is phase 7 nearly perfectly.  Go to Tropical Tidbits and see where it goes after that.  

[snowmaker]

Seems like we don't need the super arctic air to get snow, according to most models that last few runs we have too much cold which is suppressing everything to our south. In these cases a nw trend is possible I would think or at least may the arctic mass speed needs to slow down. Just don't want to see suppression, us in middle and west tn have been too far west so far this year it will be a kick in the shins for all systems go to our south. I would rather see the systems under us a 5-10 range versus north of us for sure. Maybe it's good we aren't in the bullseye still aways out, and still time for changes even some pretty big ones I would think.

[Carvers Gap]

By 180, the cold overwhelms the pattern(not in the d8-10 frame) on the 12z GEFS.  I should point out that the cold is not lurking in day 8-10.  It is much closer than that.  The coldest air is at d8-10.

[snowmaker]

Carver thank you for your almost daily briefings, I love to follow your write ups and thoughts. I am wrong in thinking that the 10th-12th timeframe might be a good time if we can catch a wave out in front and the coldest of arctic air? Excuse me for asking if my question sounds silly. 

[Carvers Gap]

IMO, if the extreme cold(both the CMC and GFS have 1060+ highs) gets into MT, we are about two cutters away from that surging into the East.  One thing to remember is that cold air is quite shallow and that wrecks havoc on modeling.  Right now, modeling has not lost the cold signal.  What it did gain was a healthy SER next week which is going to fight it.  I will take my chances on the edge with this.  Cold air is still within d7

[Daniel Boone]

9 minutes ago, Carvers Gap said:

Now take a look at next Weds on the 12z GEFS.  I cherry picked this frame(there aren't many warm ones after Sunday).  It is Tuesday, and that is phase 7 nearly perfectly.  Go to Tropical Tidbits and see where it goes after that.  

But, how's phase 7 with blocking ? That's what the model's will have trouble with.

[Carvers Gap]

Just now, snowmaker said:

Carver thank you for your almost daily briefings, I love to follow your write ups and thoughts. I am wrong in thinking that the 10th-12th timeframe might be a good time if we can catch a wave out in front and the coldest of arctic air? Excuse me for asking if my question sounds silly. 

I think right now it looks like we are getting a surge of cold about every 5 days beginning with Sunday.  The real question is whether the entire air mass comes east in one swoop.  Modeling tried that yesterday, and overnight(and so far today) modeling has pushed that back about 72-96 hours.  If the entire air mass comes out, I would "think" there is a chance for a very big storm along that front.  If the cold comes out in pieces, we will have to hope that we don't get in the "warm-up and rain" pattern after each cold snap.  Right now, we just want to see the OLR maps push precip to the dateline in the equatorial Pacific.  If they do that, I think we are in business.  If force, I would think late next week or weekend would be our next window.  However, things are changing so rapidly on modeling....I doubt M-F next week is even ironed out.  Looks like cold Sunday which will be followed by a brief but intense warm-up, followed by another strong cold front after that.  It is along that second front that I will be watching for mischief.  

[Carvers Gap]

1 minute ago, Daniel Boone said:

But, how's phase 7 with blocking ? That's what the model's will have trouble with.

Yep.  And I think the block will force that cold out of the Rockies maybe even without phase 8.

[tnweathernut]

the 12z GFSv16 finally updated.  It has a light to moderate snow on Super Bowl Sunday across much of the state.

[Bigbald]

Para looks amazing at 210

[Holston_River_Rambler]

2 hours ago, Carvers Gap said:

Bout the only thing I have used it for (other than cold yesterday) is to see if it gives me a clue to the Euro run.  

I may have been looking at it the wrong way, but that is why I use it too and it just seems like it hasn't always been great about doing that this season. 

[Stovepipe]

1 hour ago, tnweathernut said:

the 12z GFSv16 finally updated.  It has a light to moderate snow on Super Bowl Sunday across much of the state.

It took a little longer to update because it had to factor in John going to Nooga.

[Carvers Gap]

I have refereed to this winter as an odd mix of the 89-90 winter and 95-96.  Think we may be about to see both.  Anyway, I was thinking back to this event as I have seen the Euro op float this idea twice in a row now.  Charleston, SC, during December of 1989 got hammered by snowfall.  Probably doesn't make any of you feel better about our chances, but I thought that was interesting.  

https://www.postandcourier.com/news/the-legendary-snowstorm-of-89-gave-charleston-a-white-christmas-after-a-difficult-year/article_f48d8e78-f00b-11e7-aa4a-d325d9b04ec5.html

If we get December 1989 cold in February 2021, I won't complain...Feb is a much more active month in terms of precip and has increasingly changing wavelengths.  

[Holston_River_Rambler]

Everything seems to like that window between the 12th and the 14th, at least for now. Hopefully the Euro is overamping some storm somewhere that is messing with the flow. If you look at the GFS, CMC, and Euro, they look remarkably similar for such a lead.

 

 

 

 

 

 

 

 

 

 

 

[Holston_River_Rambler]

That being said, they just all handle that giant vort. lobe so differently.  It's actually kind of surprising, when you look at it that way, that they have a similar solution at the surface. 

[Carvers Gap]

3 minutes ago, Holston_River_Rambler said:

Everything seems to like that window between the 12th and the 14th, at least for now. Hopefully overamping some storm somewhere that is messing with the flow. If you look at the GFS, CMC, and Euro, they look remarkably similar for such a lead.

 

 

 

 

 

 

 

 

 

 

 

Looks like a window to follow.  If we can manage to put snow on the ground then, it might now leave for several days.  Mountains might keep snow for the rest of the month.  Interestingly, Holston, have the Smokies kept continuous snowfall on the ground since Christmas?

[Holston_River_Rambler]

5 minutes ago, Carvers Gap said:

 Interestingly, Holston, have the Smokies kept continuous snowfall on the ground since Christmas?

Not sure, but it sounds like some places at elevation def. have. 

The EPS looks more like the CMC or the new para GFS, at least to me, so it would be less suppressed and closer to the 12th than the 14th:

[Holston_River_Rambler]

Apparently the para gFS has been doing well the past week or so:

 

stolen from the MA forum 

[Carvers Gap]

45 minutes ago, Holston_River_Rambler said:

Apparently the para gFS has been doing well the past week or so:

 

stolen from the MA forum 

Great share, man.